Books:
Arbor Day Foundation. (2011). What Tree is That: A guide to the more common trees found in North America. Lincoln, NE: Arbor Day Foundation.
Plotnik, A. (2000). The Urban Tree Book: An Uncommon Field Guide for City and Town. New York: Three Rivers Press.
Websites:
http://www.arborday.org/trees/treeGuide/TreeDetail.cfm?ID=213
http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?2871
http://en.wikipedia.org/wiki/Amelanchier_arborea
http://en.wikipedia.org/wiki/Ulmaceae
http://en.wikipedia.org/wiki/Siberian_Elm
http://en.wikipedia.org/wiki/Overcup_oak
http://en.wikipedia.org/wiki/Eastern_Hophornbeam
http://en.wikipedia.org/wiki/Chinkapin_oak
http://dnr.wi.gov/forestry/TreeID/TreePgs/quercusmuehlen.htm